1. Field of Invention
This invention relates to a high-strength light-weight conductor and a twisted and compressed conductor which are used in power transmission lines, etc. and a reinforcing wire used therein.
2. Description of Prior Art
Twisted conductors are widely used in the fields from power cables to low-tension wires of electronic equipment. Among the fields is application where twisted conductors are required to be of high strength and light weight. For example, a high-strength light-weight twisted conductor, where used in power cables, will allow extension of the distance between pylons or greatly reduce wire breakage in the strong wind.
In the field of automobiles, a high-strength light-weight twisted conductor will enable reduction of a wire harness diameter and also completely prevent accidental wire breakage during routing.
To meet the above demand, various alterations to the composition of copper alloys constituting the conductor have been studied but have not achieved satisfactory results in performance and cost.
As another approach, it has been proposed to use twisted music wires (hard drawn steel wires) as a reinforcing core around which conductor wires of copper, aluminum, etc. are arranged to obtain a high-strength light-weight twisted conductors.
However, such a high-strength light-weight twisted conductor is susceptible to corrosion because of the steel wire. Further, the conductor suffers from a core loss due to the AC resistance by the skin effect, resulting in power transmission loss. Furthermore, where it is applied to low-slack overhead electric wires, it would be necessity to use expensive alloys such as invar (a nickel alloy) so as to meet the requirement for a low linear expansion coefficient.
An object of the present invention is to provide a twisted conductor which eliminates the above-described problems and provides high-strength light-weight electric wires.
The above object of the present invention is accomplished by a high-strength light-weight twisted conductor comprising a central wire and a plurality of conductor wires concentrically twisted around the central wire, wherein the central wire is at least one high-strength wire made of a fiber-reinforced metal matrix composite.
The object of the invention is also accomplished by a twisted and compressed conductor comprising a central wire and a plurality of wires concentrically twisted around the central wire, wherein the central wire is at least one high-strength wire made of a fiber-reinforced metal matrix composite.
Application of the high-strength light-weight twisted conductor of the invention to a power cable makes it possible to extend the distance between pylons and considerably reduce cable breakage in the strong wind.
Application of the high-strength light-weight twisted conductors of the invention in the automotive field, etc. makes it possible to reduce the diameter of wire harnesses and completely prevent accidental wire breakage during routing.
In a highly preferred embodiment of the invention, the central wire is made of a non-iron material so that such problems as a core loss, corrosion and heat generation can be solved. The conductor according to this embodiment is particularly suited for use in power transmission and provides low-slack overhead electric wires without needing expensive alloys such as invar.